Unlike the conventional client/server mode, a peer-to-peer (P2P) network does not have a central server node. Each node in the P2P network may serve as the server to provide services to other nodes, and may also enjoy the services provided by other node serving as the server. Therefore, in the P2P network, all nodes are equal in position, where each node is referred to as a peer.
The P2P network is a self-organized configuration network system. In the network, the behavior of joining the network or exiting the network performed by each peer is random. Similarly, in the network, for the communication between each two peers, after a relevant Key is found according to a logical distributed hash table (DHT), a lower layer physical link is randomly selected to perform the route connecting communication. Accordingly, when the number of peers or the communication throughput in the network gradually increases, the flows in the whole network become unorganized and out of order, and a great amount of data transmissions is performed through the whole network search or operation. Consequently, a backbone network with an insufficient bandwidth resource and an inter-domain link are seriously consumed, and network congestion is thereby generated.